I have a few Dell servers that I'm quite happy with. Right now you can pick up a low-end Dell with no OS for about $300.00 US. I do my web hosting and experimentation with linux, so there is no OS cost.
If you have any computers of sufficient horsepower you can usually put a server OS on and voila, instant "server". What makes a server is software, when you buy a "server" usually that implies more rugged hardware, maybe raid disks, and no multimedia stuff, otherwise a server is pretty much another pc.

Internet Information Server (IIS) comes with various editions of Windows. Its not hard to administer and IMHO a lot easier to administer than Apache.
http://www.iis.net

If you want to try Apache this is a good way to get started - http://www.apachefriends.org/en/xampp.html

Thanks a lot guys!
So, what kind of prices and I am looking at for all of this?

Kewl! ... Thanks Jeff!
Ah, ok, next question involves security.
I have a long-time friend, who is a linux proponent. He vehemently abhors Microsoft products. He has told me that Microsoft boxes are much easier to hack than linux boxes, and it happens all of the time.
What is up with this?

First off, I know very little about this subject, so take what I say with a grain of salt. this is a newbe talking ;).
For the last 5 months I've been using my laptop with xp pro with iis 5 to host a small (23 members) private nfl forum for me and my cyber buddies.
xp pro is limited to 10 connections and all the members know this. I asked them to say something when they can't connect. So far I've only had one report.

I knew when I started hosting it, that when football season started 10 connections would not be enough. I watched ebay and was able to score a used copy of microsoft server 2003 with 5 CALs (I think thats the number of web sites allowed) for $34. I haven't installed it yet but the discs are ready to go.
Just thought I'd let you know what this newbe is doing .